Guru is a guide who can understand all one's problems and suggest Mantras with the help of which one could get rid of all problems.
Mantra is a divine combination of divine syllables or sounds which when chanted with devotion,faith and emotion gravitate the concerned God or Goddess or deity and secure their divine blessings. For divine help one must link with divine forces but majority of humans are unaware of these forces and have no link whatsoever. But when an individual starts chanting Mantra related to a particular deity regularly the gap between him and the concerned divine force steadily decreases. By regular use of Mantra a subtle link is formed and through this one could then obtain any desired boon within the power of the deity. One could obtain wealth, prosperity, fame, fearlessness, success and spiritual upliftment, but for each a different Mantra is chanted and a different deity propitiated.
A Mantra is a special set of words through only that particular deity could be summoned. If I write or speak in Chinese you won't be able to understand and my words will not produce any effect. But if I speak the language you know its effect shall be with doubt. Praying to these deities in one's language won't help much but if one uses the words that they can understand the result shall be instant.
These words are the Mantras evolved by Rishis and Yogis who actually prepared them and used them to prove their worth. Over the ages these have helped thousands of Sadhaks achieve even that which appeared impossible to them. Within doubt that whose chanting fulfils one's wish is a Mantra.
Source: From a reputed web site
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